The present invention relates to a semiconductor device, for example, to a semiconductor device which controls a drive transistor of a DC voltage conversion circuit according to the magnitude of an output current.
A DC voltage conversion circuit which converts an input DC voltage into an output DC voltage having a different voltage from the input DC voltage is employed in various circuits. The DC voltage conversion circuit includes a step-down circuit which steps down an input DC voltage and a step-up circuit which steps up the input DC voltage. An example of the step-down circuit is disclosed by Patent Literature 1.
A semiconductor device disclosed by Patent Literature 1 is comprised of a controller which outputs a control signal, and a power supply unit which has a switching element ON/OFF-controlled by the control signal and which generates an output current or an output voltage corresponding to an electric current flowing through the switching element. The controller is comprised of a CPU which outputs reference voltage information; a reference voltage generator which stores the reference voltage information and generates a reference voltage based on the stored information; a comparator which compares a comparison voltage corresponding to an output current or an output voltage generated by the power supply unit, with the reference voltage; and a control signal generator which generates a control signal of a logical value corresponding to the comparison result of the comparator. According to such a configuration, the semiconductor device disclosed by Patent Literature 1 can change the output current or the output voltage promptly to a target value.
(Patent Literature 1) Japanese Unexamined Patent Application Publication No. 2013-126338